Significant increases in the density and number of lymphatic vessels in pleuroparenchymal fibroelastosis

Limited efficacy of nintedanib for idiopathic pleuroparenchymal fibroelastosis

BACKGROUND

The antifibrotic agent nintedanib has been reported to effectively prevent the decline in forced vital capacity (FVC) in a broad range of interstitial lung diseases. However, the efficacy of nintedanib against idiopathic pleuroparenchymal fibroelastosis (iPPFE) remains unclear.

METHODS

We retrospectively examined patients with idiopathic PPFE or idiopathic pulmonary fibrosis (IPF) who received nintedanib for more than 6 months. We evaluated annual changes in %FVC, radiological PPFE lesions, and body weight before and during nintedanib treatment. To investigate radiological PPFE lesions, we examined the fibrosis score, which was defined as the mean percentage of the high attenuation area in the whole lung parenchyma using three axial computed tomography images.

RESULTS

Overall, 15 patients with iPPFE and 27 patients with IPF were included in the present study. In patients with IPF, the annual rate of decline in %FVC was significantly lower during nintedanib treatment than that before treatment (-2.01%/year [-7.64 to 3.21] versus -7.64%/year [-10.8 to -4.44], p = 0.031). Meanwhile, in patients with iPPFE, the annual rate of decline in %FVC during nintedanib treatment was higher than that before treatment (-18.0%/year [-21.6 to -12.7] versus -9.40%/year [-12.3 to -8.23], p = 0.109). In addition, nintedanib treatment failed to inhibit the annual rate of increase in fibrosis score in patients with iPPFE (6.53/year [1.18-15.3] during treatment versus 2.70/year [0.27-12.2] before treatment, p = 0.175).

CONCLUSIONS

Nintedanib efficacy may be limited in patients with iPPFE.

Paradoxical Formation of a Pleuroparenchymal Fibroelastosis-like Lesion in the Chronic Course of Pulmonary Sarcoidosis

We herein report the long-term changes in chest computed tomography (CT) findings from early sarcoidosis lesions to pleuroparenchymal fibroelastosis (PPFE)-like lesions in a 30-year-old man with granulomas on a transbronchial lung biopsy. Multiple bilateral micronodular and nodular opacities around the bronchovascular bundle in the upper lobes detected by chest CT in 2004 disappeared, but paradoxically, peripheral consolidations continued to grow at the periphery of the original lesions. Chest CT in 2017 confirmed the progression of bilateral shrinkage of the upper lobe, spread of peripheral consolidations and wedge-shaped opacities below the first rib, and bronchiectatic air bronchograms, confirming PPFE-like lesions.

Platythorax progresses with lung involvement in pleuroparenchymal fibroelastosis

BACKGROUND

Patients diagnosed with pleuroparenchymal fibroelastosis (PPFE) exhibit unique clinical features, including upper lobe-dominant lung involvement and platythorax (or flattened thoracic cage). Although platythorax have been shown to be a sign of disease progression, the temporal relationship between the progression of platythorax and the extent of lung involvement has not been closely investigated.

METHODS

We retrospectively investigated patients diagnosed with PPFE, who did not exhibit fibrotic lesions other than PPFE in the lower lobes. We estimated the fibrosis score, which is a visual score indicating the percentage of lung parenchyma occupied by the disease on computed tomography images selected every 2 cm from the lung apex to the lung base, and the flat chest index (the ratio of the anteroposterior diameter of the thoracic cage to the transverse diameter of the thoracic cage). Additionally, we investigated serial changes in the flat chest index and fibrosis score.

RESULTS

A total of 29 patients were included in this study. The fibrosis score was found to be weakly and inversely correlated with forced vital capacity %predicted at the diagnosis (r = -0.40, p = 0.038). Furthermore, the annual changes in the flat chest index and fibrosis score was found to be moderately and inversely correlated (r = -0.663, p = 0.0037).

CONCLUSIONS

These results indicate that there is a causal relationship between the progression of fibroelastosis and that of platythorax in patients with PPFE.

Pleuroparenchymal fibroelastosis: Clinical, radiological and histopathological features

Pleuroparenchymal fibroelastosis (PPFE) is a rare, generally idiopathic form of interstitial pneumonia with unique clinical, radiological and histopathological features. It is named after the presence of upper lobe pleural and subjacent parenchymal fibrosis, with accompanying elastic fibers. Although it is usually an idiopathic disease, it has been linked to other co-existent diseases. Diagnostic suspicion of PPFE is based on the identification of typical abnormalities on chest CT scan, which are prevailingly located in the upper lobes, adjacent to the apex of the lungs. Diagnosis can be confirmed by histological analysis, although biopsy is not always feasible. The disease is generally progressive, but not uniformly. The course of the disease is frequently slow and involves a progressive loss of upper lobe volume, which results in platythorax, associated with a significant reduction of body mass. PPFE concomitant to other interstitial lung diseases is associated with a poorer prognosis. The disease occasionally progresses rapidly causing irreversible respiratory insufficiency, which leads to death. Currently, there is no effective pharmacological therapy available, and lung transplantation is the best therapeutic option. The purpose of this review is to draw the attention to PPFE, describe its clinical, radiological and histopathological features, analyze its diagnostic criteria, and provide an update on the management of the disease.

Severe and progressive platythorax disproportionate to lung fibrosis: A rare variant of idiopathic pleuroparenchymal fibroelastosis

A 57-year-old man was referred to our department because of progressive shortness of breath and emaciation. He had experienced pneumothorax three times in the past five years. The patient radiologically showed mild upper-lobe predominant airspace consolidation and severe platythorax and was clinically diagnosed with idiopathic pleuroparenchymal fibroelastosis (PPFE). Although the wedge-shaped shadows in the bilateral lung apexes did not significantly progress, his platythorax gradually worsened during the clinical course. He ultimately died of chronic respiratory failure 1.2 years after the diagnosis. This case demonstrates a rare variant of idiopathic PPFE with progressive platythorax disproportionate to the extent of upper-lobe fibroelastosis.

The pathogenesis and pathology of idiopathic pleuroparenchymal fibroelastosis

Idiopathic pleuroparenchymal fibroelastosis (IPPFE) is a rare subtype of idiopathic interstitial pneumonias that consists of elastofibrosis involving the lung parenchyma and pleural collagenous fibrosis predominantly located in the upper lobes. IPPFE has various distinct clinical and physiological characteristics, including platythorax and a marked decrease of forced vital capacity with an increased residual volume on a respiratory function test. The concept of IPPFE is now widely recognized and some diagnostic criteria have been proposed. In addition, the accumulation of cases has revealed the pathological features of IPPFE. However, little is known about the pathogenesis or the process of disease formation in IPPFE. This review article will provide a summary of the pathological features and previously reported hypotheses on disease formation in IPPFE, to discuss the potential etiologies and pathogenesis of IPPFE.

Physiological Criteria Are Useful for the Diagnosis of Idiopathic Pleuroparenchymal Fibroelastosis

BACKGROUND

Diagnostic criteria of idiopathic pleuroparenchymal fibroelastosis (IPPFE) were recently proposed, including physiological criteria of the body mass index (BMI) and percentage of the predicted values of residual volume (RV)/total lung capacity (TLC) (RV/TLC %pred.). The aim of this study was to evaluate (i) whether the physiologic criteria are useful for the diagnosis and (ii) whether the flat chest index, defined as the ratio of the anteroposterior diameter to the transverse diameter of the thoracic cage, could be an alternative parameter to RV/TLC %pred.

METHODS

We selected consecutive IPPFE patients and idiopathic pulmonary fibrosis (IPF) patients. We examined the diagnostic sensitivity and specificity of the physiological criteria and flat chest index for differentiating IPPFE patients from IPF patients.

RESULTS

This study included 37 IPPFE patients and 89 IPF patients. The physiological criteria distinguished IPPFE patients from IPF patients with a sensitivity of 78.6% and specificity of 88.0%. The combination of the flat chest index and BMI was also effective for differentiation (sensitivity of 82.1% and specificity of 89.3%).

CONCLUSION

We verified the good performance of the physiologic criteria in a different cohort. When the RV/TLC is not measured, using the flat chest index instead of RV/TLC %pred. may be reasonable.

Unilateral upper lung-field pulmonary fibrosis radiologically consistent with pleuroparenchymal fibroelastosis after thoracic surgery: Clinical and radiological courses with autopsy findings

BACKGROUND

Pleuroparenchymal fibroelastosis (PPFE) is a rare idiopathic interstitial pneumonia characterized by pleural and parenchymal involvements predominantly in the upper lobes. Unilateral upper-lung field pulmonary fibrosis (upper-PF) radiologically consistent with PPFE was recently reported in patients with a history of open thoracotomy and presented with impaired thoracic movements in the operated side with unknown mechanisms. This retrospective study aimed to elucidate the clinical and radiological courses and pathological findings of unilateral upper-PF.

METHODS

All the consecutive patients diagnosed as having unilateral upper-PF between March 2012 and April 2018 were included. Radiological images and clinical courses before and after the diagnosis were thoroughly reviewed.

RESULTS

Fourteen patients were included. Unilateral upper-PF was diagnosed after a median of 4.8 years from the open thoracotomy or video-assisted thoracic surgery for treating lung or esophageal cancer, or bronchiectasis. Before or at diagnosis, 12 (85.7%) of 14 patients developed aberrant intrathoracic/extrathoracic air suggestive of pleural fistula, although the degree was slight. Of note, the upper-PF lesion apparently deteriorated once aberrant air emerged in all the patients. After diagnosis, the upper-PF lesion transformed into cystic lesion in 9 patients, 4 of whom eventually developed pulmonary aspergillosis. The prognosis was poor, with a median overall survival of 49.3 months. The autopsy in one patient demonstrated findings consistent with PPFE and chronic pleuritis.

CONCLUSIONS

Unilateral upper-PF developed after thoracic surgeries and had many clinical, radiological, and pathological characteristics in common with idiopathic PPFE. Our results indicate that the commonly observed aberrant air may be correlated with disease development and progression.

Serum latent transforming growth factor-β binding protein 4 as a novel biomarker for idiopathic pleuroparenchymal fibroelastosis

BACKGROUND

Idiopathic pleuroparenchymal fibroelastosis (IPPFE) is a rare idiopathic interstitial pneumonia characterized by an upper lobe-dominant interstitial increase in predominantly elastic fibers. The accumulation of cases has resulted in a refinement of the disease concept, but there are no blood biomarkers to aid in the diagnosis or prediction of a progressive phenotype among PPFE patients. Several organizers, including latent transforming growth factor-β binding protein 4 (LTBP-4), are known to be involved in elastogenesis. However, the potential of LTBP-4 as a blood biomarker for PPFE has not been investigated.

METHODS

We selected cases of clinically or histologically diagnosed IPPFE (n = 20) along with idiopathic pulmonary fibrosis (IPF) patients (n = 39) and healthy controls (n = 10). We quantified the protein levels of LTBP-4 in lung tissues and serum samples.

RESULTS

The LTBP-4 levels in lung tissue of PPFE patients were 2.16 times higher than those of IPF patients (p = 0.032). The serum concentration of LTBP-4 (pg/ml) in IPPFE was higher than that in healthy controls (1429 [154-3620] vs. 187 [56.4-490], p = 0.013). The serum concentration of LTBP-4 in IPPFE was markedly higher than that in IPF without a significant difference (1429 [154-3620] vs. 915 [491-1967], p = 0.671). In addition, a higher concentration of LTBP-4 was associated with a poor prognosis in IPPFE patients.

CONCLUSIONS

The serum concentration of LTBP-4 may aid in the diagnosis of IPPFE or the prediction of an aggressive phenotype.

Role of alveolar collapse in idiopathic pleuroparenchymal fibroelastosis

BACKGROUND

Zonal aggregates of elastic fibres (zonal elastosis) and intraalveolar collagenosis with septal elastosis are histologic components of subpleural fibroelastosis of idiopathic pleuroparenchymal fibroelastosis (IPPFE). Zonal elastosis is considered to result from alveolar collapse, but this mechanism has not been fully justified.

METHODS

We immunohistochemically attempted to identify epithelial cells in zonal elastosis of 10 patients with IPPFE. The thickness of the zonal elastosis in relation to the total thickness of the fibroelastosis was examined to estimate the influence of zonal elastosis on the occurrence and development of IPPFE.

RESULTS

In 9 of the 10 patients, multi-cytokeratin-positive cells were found lining the inner surface of slit-like spaces embedded in the zonal elastosis. Zonal elastosis was predominant when fibroelastosis was < 1 mm thick but less predominant when it was ≥1 mm.

CONCLUSION

The zonal elastosis was proven to result from alveolar collapse, which might be an initial lesion in IPPFE. (Sarcoidosis Vasc Diffuse Lung Dis 2020; 37 (2): 212-217).

An Autopsy Case of Idiopathic Pleuroparenchymal Fibroelastosis with Left Vocal Cord Paralysis and a Rapid Deterioration without an Acute Exacerbation

Idiopathic pleuroparenchymal fibroelastosis (IPPFE) is a generally slow-progressing rare disorder of unknown etiology. The direct cause of death in cases of IPPFE is rarely investigated. We experienced an autopsy case of a Japanese man with IPPFE and found aspiration pneumonia to be the major trigger of death. The individual had left vocal cord paralysis at admission, which may have contributed to aspiration pneumonia, and which probably was affected by the fibrous adhesion of the left apex of the chest wall resulting from IPPFE. The prevention of aspiration pneumonia is important for maintaining the respiratory function, especially in IPPFE patients with repeated pneumothorax.

Pleuroparenchymal Fibroelastosis. A Review of Clinical, Radiological, and Pathological Characteristics

Pleuroparenchymal fibroelastosis (PPFE) is an unusual pulmonary disease with unique clinical, radiological, and pathological characteristics. Designated a rare idiopathic interstitial pneumonia in 2013, its name refers to a combination of fibrosis involving the visceral pleura and fibroelastotic changes predominating in the subpleural lung parenchyma. Although a number of disease associations have been described, no single cause of PPFE has been unequivocally identified. A diagnosis of PPFE is most commonly achieved by identifying characteristic abnormalities on computed tomographic scans. The earliest changes are consistently located in the upper lobes close to the lung apices, the same locations where subsequent disease progression is also most conspicuous. When sufficiently severe, the disease leads to progressive volume loss of the upper lobes, which, in combination with decreased body mass, produces platythorax. Once regarded as a slowly progressing entity, it is now acknowledged that some patients with PPFE follow an inexorably progressive course that culminates in irreversible respiratory failure and early death. In the absence of effective medical drug treatment, lung transplant remains the only therapeutic option for this disorder. This review focuses on improving early disease recognition and evaluating its pathophysiological impact and discusses working approaches for its management.

Pleuroparenchymal fibroelastosis as a histological background of autoimmune diseases

Patients with autoimmune disease-related interstitial lung disease (AID-ILD) occasionally develop radiologic pleuroparenchymal fibroelastosis (PPFE)-like lesions. However, the significance of AID as an etiology of PPFE has not been fully elucidated. The aim of this study is to verify the increase of elastic fibers in AID-ILD patients and evaluate the prevalence of histological PPFE in patients with AID-ILD. We selected cases of clinically diagnosed AID-ILD and idiopathic pulmonary fibrosis (IPF), in which an autopsy had been performed or in which the patient had undergone pneumonectomy for lung transplantation. We quantified the collagen fibers and elastic fibers in each lobe as the percentage of the non-aerated lung area (collagen fiber score and elastic fiber score, respectively) in histological specimens from a total of 73 patients (AID-ILD, n = 24; IPF, n = 49). There were no significant differences in the collagen fiber scores of the AID-ILD and IPF groups. Meanwhile, the elastic fiber scores of the AID-ILD group were significantly greater than those of the IPF group in the whole lung (17.3 ± 7.70 vs 11.6 ± 4.55), and the upper (16.6 ± 8.11 vs 11.2 ± 5.18), and lower (18.0 ± 9.68 vs 12.0 ± 5.55) lobes (all p < 0.01). Histological PPFE pattern was found in 12 of 24 AID-ILD patients (50%), and histological PPFE pattern as a dominant pattern of fibrosis was found in 2 of the 24 patients (8%). Thus, PPFE can be a manifestation of AID-ILD.

Cryobiopsies are diagnostic in Pleuroparenchymal and Airway-centered Fibroelastosis

BACKGROUND

Idiopathic pulmonary fibroelastosis (iPPFE) is a rare lung lesion characterized by pleural and subpleural parenchymal thickening due to accumulation of fibroelastotic tissue. Only recently, a few cases with a peribronchiolar distribution of fibroelastotic tissue have been reported. These lesions are more prominent in the upper lobes. Even though high resolution computed tomography (HRCT) scan features are considered characteristic, a histological confirmation is suggested, mainly when the clinical setting is not clearly defined. However, due to non-negligible complications, a surgical lung biopsy is not often recommended. The prognosis is usually poor and currently, the only effective treatment is lung transplantation.

METHOD

Patients with a multidisciplinary diagnosis of iPPFE or airway-centered fibroelastosis (airway-centered FE), with histological confirmation by transbronchial cryobiopsy, were identified from an ongoing interstitial lung disease registry. Data on patient demographics, HRCT patterns, size and number of biopsies, histology patterns and complications were registered.

RESULTS

Seven patients were diagnosed with iPPFE and one patient was diagnosed with airway-centered FE. Pneumothorax was documented in three cases, but none of them required a chest tube. No other complications during or after the procedure were observed.

CONCLUSION

This study suggests that using cryobiopsies in the diagnostics of PPFE and airway-centered FE is safe and effective.